Among all the sources of pollutants in the atmosphere, the transportation industry generally is a significant contributor. For example, in the United States, the transportation industry consumes a majority of the crude oil, much of which is used by automobiles. Hence, any advances in energy efficiency, especially in the transportation industry, may correspondingly lead to reduction in energy consumption, which not only cumulatively decreases energy costs, but also cumulatively contributes to a greener environment and greater energy independence and security.
Increasing demand for better fuel economy has led to improvements and developments in hybrid vehicles, electric vehicles and vehicles powered by fuel cells or diesel fuel. Efforts on the part of the automotive industry to increase fuel economy have included, but are not limited to, reductions in vehicle mass, improved aerodynamics, active fuel management, direct injection engines, homogeneous charge compression ignition engines and hybrid engines. Still, other mechanisms, techniques and energy sources that will improve fuel economy are continually being sought.
Currently, about 10 to 16% of the available fuel energy is used to drive an automobile, overcoming the friction and drag force from the road and wind. Besides engine cycle efficiency, one important mechanism of energy loss in automobiles is the dissipation of kinetic energy during vehicle vibration and motion. In the past hundred years, the automotive industry has been working hard to dissipate the motion and vibration energy into waste heat by optimal design of braking and suspension systems and by employing active controls, such as anti-lock braking systems or active suspensions. During the past ten years, energy recovery from braking has achieved great commercial success in hybrid vehicles. However, regenerative vehicle suspensions, which have the advantage of continuous energy recovery, have generally not come into practice due to various factors, such as insufficient vibration control, unsatisfactory energy harvesting, prohibitive costs, high complexity, practical incompatibility and relative inefficiency.
In view of the foregoing, it would be desirable to provide a regenerative vehicle suspension technology that takes into account the aforementioned factors.